A wide variety of stock shoe inlays are currently available for helping to accommodate a number of foot conditions, or to adjust biomechanical parameters that affect foot, leg, and back pain during walking and running. Stock shoe inlays, available in pre-made shapes and sizes, are intended to provide one or more of the following functions: heel cushioning, longitudinal arch support, take up of extra room in shoe, and absorption of odors. Although stock shoe inlays are often convenient (they can be simply placed in the shoe and used immediately) they lack a custom fit and are not always able to provide the customer's desired function.
Custom fit shoe inserts, meant to fit directly to an individual's shoe, also exist. One such insert is composed of a bladder shaped to fit into a shoe and containing a water foamable resin. When water is injected into the bladder, the resin foams, causing the bladder to become shaped to the foot. Unfortunately, this insert is inconvenient to form and also inherently lacks porosity. The lack of porosity can make the insert feel sweaty and uncomfortable. Another insert is composed of a gel contained within membrane layers. When pressure is exerted against the insert, the gel moves to accommodate the shape of the foot. Again, this insert lacks porosity. Yet another insert is composed of a series of bladders into which air is pumped to achieve support under a foot. Unfortunately, this insert lacks a true custom fit and also lacks porosity.
Alternatively, professionally crafted custom shoe inserts are available that are custom-shaped to an individual's feet. These inserts are typically constructed by a trained professional to provide additional functionality, including heel pad containment, lateral arch support, more effective longitudinal arch support, and correction for abnormal biomechanics, such as pronation and supination. These professionally crafted custom-shaped inserts can be expensive. Previous custom-shaped shoe inserts are typically constructed by (i) preparing a mold of the foot, for example with Plaster-of-Paris; (ii) forming the custom shoe insert components on the mold, for example by thermoforming; and then (iii) machining the construction to fit the shoe. Taken together, all of these steps can take days or weeks to complete.
What is needed is a custom-formable, preferably porous, shoe insert that is easy and inexpensive to customize.